Kid walking- rotoscoped from film clip.
Back in the day this was done laboriously via a projection system drawn frame by frame onto pegged animation paper. Then it was filmed on an animation stand, film processed, then viewed on a moviola. This took about 3 days. Now, the same thing is accomplished by simply tracing layers in a pshop file on a Cintiq tablet. Two hours, tops. Technology is quite something if you've experienced both.